This invention relates to foundation ventilators of the type used to provide ventilation in crawl spaces beneath houses. It is customary to open the foundation ventilators in the spring and close them in the fall to ensure proper ventilation during the warmer months while minimizing heat loss during the colder months. Thermostatically controlled ventilators are used to open and close the ventilators automatically without attention.
The installation of foundation ventilators in masonry walls once required the skill of a craftsman. Recently, efforts have been made to provide foundation ventilators of a construction enabling the average homeowner to place the foundation ventilator an existing opening in a foundation wall. See, for example, U.S. Pat. No. 4,274,330 issued June 23, 1981 to Alvin E. Witten, et al. for VENTILATOR AND MOUNTING FRAME ASSEMBLY. According to Witten, the assembly of the ventilator in an opening in a foundation wall is a two step process. First, a rectangular hollow frame is assembled in the opening with specially designed fasteners and clamps, and the ventilator is then assembled within the hollow frame. U.S. Pat. No. 4,175,480 issued Nov. 27, 1979 to Dennis A. Beam et al. for WALL VENTILATOR CONSTRUCTION discloses a ventilator housing and frame which are connected together by the same bolts used to fasten the ventilator in an opening in a foundation wall. In both Witten and Beam the mounting frame is a hollow rectangle and the ventilator housing is enclosed with a screen on the front and rear. It is necessary, according to the prior art as represented by Witten and Beam, to remove the ventilator housing from the opening in the foundation wall and/or to remove the rear wall of the housing in order to service the louvers or operating mechanism within the ventilator housing. Such servicing is periodically necessary to remove debris and insects which accumulate within the ventilator housing and tend to interfere with the automatic functioning of thermostatically controlled foundation ventilators.